3-substituted amino-6-chloropyridazines as antioxidants for rubber



United States Patent Analysis for 0511 16 01;

3,296,187 3-SUBSTITUTED AMINO--CHLOROPYRIDAZINES AS ANTIOXIDANTS FORRUBBER Calculated Found Douglas I. Relyea, Pompton Plains, N.J.,assignor to 5 United States Rubber Company, New York, N.Y., 2 Percent C5175 51 68 corporation of New Jersey Percent H, GI 2 61 No Drawing.Filed June 26, 1963, Ser. No. 290,592 Percent 18-93 10 Claims. Cl.260-458 PmemN- 22-63 22-41 This application is a continuation-in-part ofmy applica- 10 tion Serial No. 233,877, filed October 29, 1962, now US.EXAMPLE 2 I 1, {0 re int i fi i 3611b: were prepared otheraminochloropyridazines by substitutfi 2, 0 5 enresenlt db the for ingequimolar proportions of di-n-butylamine, cyclom1u1a a 1 oropyn 1 es I pe hexylamine, aniline, and isopropylamine for the n-butylamine ofExample 1. Melting points of these chemicals were as follows-t v A :"C.3-di-n-butylamino-6-chloropyridazine 5758 0 3-cyclohexylamino-6chloropyridazine 167168 wherein R is monoalkylamlflo, y cycloalkyl-2-anilino-6-chloropyridazineI 178-181 amino anilil'lo- The alkyl groupsIn the monoalkyl' 3-isopropylamino-6-chloropyrida2ine 110112 amino anddialkylamino radicals will have from 1 to 8 25 1 v carbon atoms, e.g.,methyl, ethyl, propyl, butyl, hexyl, Analyses-for the above fourcor'npoundsin the order octyl. The cycloalkyl group in thecycloalkylamino radgiven above are shown 'inthe following table:

Calculated Found Percent Percent Percent Percent Percent Percent PercentPercent O H C1 N C H Cl N Analysis for: 3 5

01 131001 01 59. 61 8.35 14.67 60.82 8. 53 14.66 CioH14N3C1 56.73 6.6616.75 19. 85 57.95 6.81 16.70 19.76 CroHgNaCl 58.40 3.92 17.24 20. 4361.00 4.21 15.24 20.21 C1H10N3C1 48. 99 5.87 20.66 24.48 48.86 6.1120.64 24.13

ical will have from 5 to 8 carbon atoms, e.g., cyclopentyl, Thechemicals of the present invention are anti-oxidants cyclo-hexyl,cyclooctyl. for rubbers, such as natural rubber and synthetic rubbers,The chemicals of the present invention are prepared and mixturesthereof. The synthetic rubbers may be the by reacting3,6-dichloropyridazine, a known chemical, products of aqueous emulsionpolymerizations with a with the selected amine in an inert solvent,e.g., ethanol, peroxide catalyst of various rubber-forming monomers.xylene, benzene, pyridine, dioxane. Such synthetic rubbers may bepolymers of butadienes-1,3

Examples 1 and 2 illustrate the preparation of the e.g. butadiene-lfi,2-methylbutadiene-1,3 (isoprene), 2- chemicals of the present invention.chlorobutadiene-1,3 (chloroprene), 2,3-dimethylbutadiene-1,3,piperylene, and copolymers of mixtures thereof,

EXAMPLE 1 and copolymers of mlxtures of one or more such butad1enes-1,3with up to 70% of such mixtures of one or more monoethylenic compoundswhich contain a Prepfll'lliwfl f y opyl'ldazme CH =C group where atleast one of the disconnected valences is attached to anelectro-negative group, that is A soluuon of 74.5 gm. (0.5 mole) of -f agroup which substantially increases the electrical dis- Pyndazme 250 ofF f Pyndlne w mixed Wlth symmetry or polar character of the molecule.Examples 99 ml. (1.0 mole) of redistilled n butylamine. The cleag ofSuch monoethylenic Compounds which are copolym Sohmon was heated atreflux (112 for 9 hours an erizable with butadienes-1,3, are arylolefins, such as then transferred to a beaker containing 2 liters ofwater 0 which was being agitated vigorously. The precipitate thus formedwas separated from the light brown liquid by filtration, thoroughlywashed with 2 liters of Water and subsequently redissolved in 88 ml.(1.07 moles) of cone. HCl and 150 ml. of water and reprecipitated in 2liters of water containing 100 gm. of sodium hydroxide. The whiteprecipitate was washed three more times, using 2 liters of water eachtime. After the third washing, the wash water showed no reaction tolitmus paper. The product was then dried at 50 C. (and 50 mm. pressure),resulting in gm. of 3-n-butylamino-6-chloropyridazine having a meltingpoint of 1l0.9-111.5 C.

styrene, vinyl naphthalene, alpha-methylstyrene, parachlorosty-rene,dichlorostyrene, alpha-methyldichlorostyrene; the alpha methylenecarboxylic acids and their esters, nitriles andamides, such as acrylicacid, methyl acrylate, methyl methacrylate, acrylonitrile,methacrylonitrile, methacrylamide; methyl vinyl ether; methyl vinylketone; vinylidene chloride; vinyl pryidines, such as 2-vinyl pyridine,2-methyl-5-vinyl pyridine; vinyl carbazole. Commercial synthetic rubbersof this type are SBR (copolymer of a major proportion of butadiene and aminor proportion of styrene) and NBR (copolymer of a major (proportionof "butadiene' and a ininor proportion of acrylonitri'le). The syntheticrubber may also be a 1, 4-polybutadiene or a 1,4-pol'yisoprene, preparedby solution polymtional testing methods used for rubber with results asshown in the following table:

Time of Physical Properties cure, A B C D E minutes 30 3 660 3 910 3 8 3600 4 090 115118 strength 90 3; 750 31 560 31 640 3: 650 31 640Elongation at Break (Percent). 30 1,850 1 675 1 750 1 725 1 500 Modulusat 300% i 90 1, 600 1: 425 1: 550 1: 425 1; 225 Aged in air at 212717530 1 610 1 520 1 880 1 600 1 e00 Telsne Strength i 90 1: 270 1:240 1:39011 140 1: ago Elongation at Break (Perce11t) F so 2 000 1 925 2 000 1875 2 200 Mdulus at 300% 90 1: 750 1: 500 1: 625 1: s75 1:850

1 Extrapolated values.

erization. Such 1,4-polybutadiene may be made by solu tionpolymerization of butadiene-1,3 in the presence of a catalyst reactionproduct of an aluminum trialkyl, such as aluminum triethyl, and titaniumiodide. Such 1,4- polyisoprene may be made by solution polymerization ofisoprene in the presence of a catalyst reaction product of an aluminumtrialkyl, such as aluminum triisobutyl, and titanium tetrachloride. Thesynthetic rubber may also be the product of the solution polymerizationof a mixture of a major proportion of isoolefin and a minor proportionof conjugated diene at low temperature in the presence of aFriedel-Crafts polymerization catalyst of the type of aluminum chlorideor boron trifiuoride. An example of a commercial synthetic rubber ofthis type is butyl rubber which is a copoly'mer of about 95 to 99 partsof isobutylene and correspondingly to 1 parts of isoprene. The syntheticrubber may also be the product of the solution polymerization of amixture of ethylene and at least one alpha olefin having the formula CH=CHR in which R is an alkyl radical having 1 to 8 carbon atoms, e.gpropylene, with a minor proportion of a non-conjugated diene, such as1,4-hexadiene or dicyclopentadiene, in the presence of a catalystreaction product of aluminum trialkyl, and titanium tetrahalide orvanadium tetrahalide or vanadium oxytrihalide, e.g. the reaction productof aluminum tridecyl and vanadium oxytrichloride. An example of asynthetic rubber of this type is a terpolymer of about 55% propylene,41% ethylene and 4% 1,4-hexadiene. The amount of antioxidant will befrom 0.1 to 5 parts by weight per 100 parts of the rubber.

EXAMPLE 3 This example illustrates the effectiveness of variouschemicals of the present invention as antioxidants forsulfur-vulcanizable rubbers, such as natural rubber.

Five rubber stocks A to E were compounded on a tworoll mill by mixinginto 100 parts of Hevea rubber, 2 parts of stearic acid, 45 parts of HAF(high abrasion furnace) carbon black, 3 parts of zinc oxide, 6 parts ofParaflux softener (a saturated polymerized petroleum hydrocarbon havinga specific gravity of 1.02 and a Saybolt Furol Viscosity of 250-350seconds at 140 F.), 2.75 parts of sulfur and 0.75 part ofN-cyclohexyl-Z-benzothiazolesulfenamide accelerator. For testing asantioxidants, there was incorporated in stocks A, B, C and D 2 parts of3-nbutylamino-6-chloropyridazine, 3-di-n-butylamino-6-chloropyridazine,3-cyclohexylamino-6-chloropyridazine, and 3-anilino-6-chloropyridazine,respectively. For comparison purposes, there was incorporated in stock Ea conventional commercial antioxidant combination, viz. 2.0 parts of BLE(a high temperature reaction product of diphenylamine and acetone havinga specific gravity of 1.09) and 0.35 part of JZF(N,N'--diphenyl-p-phenylenediamine).

Specimens of stocks A to B were cured-in a press for 30 and 90 minutesat 293 F. and tested by the conven- The above data demonstrate that thechemicals of the present invention are equally as elfective with respectto aging characteristics after 72 hours exposure in air at 212 F. as theconventional commercial antioxidant combination.

In view of the many changes and modifications that may be made withoutdeparting from the principles under. lying the invention, referenceshould be made to the appended claims for an understanding of the scopeof the protection afforded the invention.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. A sulfur-vulcanizable diene rubber composition comprising 0.1 to 5parts by weight per parts of rubher of a compound represented by theformula wherein R is selected from the group consisting ofmonoalkylamino, dialkylamino, cycloalkylamino and anilino.

2. A sulfur-vulcanizable diene rubber composition by weight per 100parts of rubber of a compound represented by the formula wherein R isselected from the group consisting of monoalkylamino, dialkylamino,cycloalkylamino and anilino.

7. A composition comprising a vulcanized sulfur-vulcanizable dienerubber stock containing 0.1 to 5 parts 'by Weight of3-n-butyla'mino-6-chloropyridazine per 100 parts of rubber.

8 A composition comprising a vulcanized sulfur-vulcauizable diene rubberstock containing 0.1 to 5 parts by weight of3-di-n-butylarnino-6-chloropyridazine per 100 parts of rubber. I 9. Acomposition comprising a vulcanized su1fur-vul- 5 6 caniza'ble dienerubber stock containing 0.1 to 5 parts by References Cited by theExaminer Weight of 3-cyc1ohcxy1amino-6-chloropyridazine per 100 FOREIGNPATENTS parts of rubber.

10. A composition comprising a vulcanized sulfur-vul- 822,069 10/1959Great Bntam' canizable diene rubber stock containing 0.1 to 5 parts by 5g weight of 3-ani1ino-6-chloropyridazine per 100 parts of LEONJ'BERCOVITZPrlmary Exammer rubber. M. I. WELSH, Assistant Examiner.

1. A SULFUR-VULCANIZABLE DIENE RUBBER COMPOSITION COMPRISING 0.1 TO 5PARTS BY WEIGHT PER 100 PARTS OF RUBBER OF A COMPOUND REPRESENTED BY THEFORMULA